U.S. patent number 11,096,049 [Application Number 16/319,996] was granted by the patent office on 2021-08-17 for connection of wearable devices.
This patent grant is currently assigned to IPCOM GMBH & CO. KG. The grantee listed for this patent is IPCom GmbH & Co. KG. Invention is credited to Martin Hans, Achim Luft.
United States Patent |
11,096,049 |
Luft , et al. |
August 17, 2021 |
Connection of wearable devices
Abstract
The present invention provides a method for enabling a wearable
device connected to a user equipment device to be identified and
authenticated within a mobile communications network, the method
comprising attaching both the user equipment device and the
wearable device to the mobile communications network by means of a
single registration request communicated by the user equipment
device to the mobile communications network.
Inventors: |
Luft; Achim (Braunschweig,
DE), Hans; Martin (Bad Salzdetfurth, DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
IPCom GmbH & Co. KG |
Pullach |
N/A |
DE |
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Assignee: |
IPCOM GMBH & CO. KG
(Pullach, DE)
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Family
ID: |
1000005747613 |
Appl.
No.: |
16/319,996 |
Filed: |
July 26, 2017 |
PCT
Filed: |
July 26, 2017 |
PCT No.: |
PCT/EP2017/068884 |
371(c)(1),(2),(4) Date: |
January 23, 2019 |
PCT
Pub. No.: |
WO2018/019883 |
PCT
Pub. Date: |
February 01, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190274110 A1 |
Sep 5, 2019 |
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Foreign Application Priority Data
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Jul 26, 2016 [EP] |
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16181302 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L
63/0884 (20130101); H04W 4/80 (20180201); H04W
60/06 (20130101); H04W 76/25 (20180201); H04W
8/20 (20130101); H04W 8/04 (20130101); H04W
8/08 (20130101); H04W 76/11 (20180201); H04W
76/15 (20180201); H04W 12/06 (20130101); H04W
88/04 (20130101); H04W 68/02 (20130101) |
Current International
Class: |
H04W
12/06 (20210101); H04W 76/25 (20180101); H04W
4/80 (20180101); H04W 76/11 (20180101); H04W
8/20 (20090101); H04W 60/06 (20090101); H04W
8/08 (20090101); H04W 68/02 (20090101); H04W
76/15 (20180101); H04L 29/06 (20060101); H04W
8/04 (20090101); H04W 88/04 (20090101) |
Field of
Search: |
;370/310,328,329 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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WO-2012035335 |
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Mar 2012 |
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WO |
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Other References
International Search Report for International Application No.
PCT/EP2017/068884, dated Nov. 7, 2017. cited by applicant .
3rd Generation Partnership Project; Technical Specification Group
Services and System Aspects; Study on Facilitating Machine to
Machine Communication in 3GPP Systems; (Release 8), 3GPP Standard;
3GPP TR 22.868., 3rd Generation Partnership Project (3GPP), Mobile
Competence Centre; pp. 1-15, XP050361381, Mar. 1, 2007. cited by
applicant .
European Patent Office Examination Report for Application No. EP 17
742 447.0, dated Feb. 15, 2021. cited by applicant.
|
Primary Examiner: Huq; Obaidul
Attorney, Agent or Firm: Marshall, Gerstein & Borun
LLP
Claims
The invention claimed is:
1. A method for enabling a wearable device connected to a user
equipment device to be identified and authenticated within a mobile
communications network, the method comprising: attaching both the
user equipment device and the wearable device to the mobile
communications network by means of a single registration request
communicated by the user equipment device to the mobile
communications network, wherein the single registration request
comprises an identity of the user equipment device and an identity
of the wearable device, and wherein the user equipment device and
the wearable device are authenticated within a mobile management
entity of the mobile communications network with a dedicated
challenge response mechanism against (i) a subscriber identity
module of the user equipment device using the identity of the user
equipment device, and (ii) a subscriber identity module of the
wearable device using the identity of the wearable device.
2. The method according to claim 1, wherein the identity of the
user equipment device is one of an international mobile subscriber
identity and a temporary identity stored in the user equipment
device.
3. The method according to claim 1, wherein the wearable device is
connected to the user equipment device by a radio connection.
4. The method according to claim 1, wherein the user equipment
device provides information to the mobile communications network
about one or more capabilities of the wearable device.
5. The method according to claim 1, wherein the attachment of the
wearable device to the mobile communications network may be ended
leaving the attachment of the user equipment device to the mobile
communications network unaffected.
6. The method according to claim 5, wherein a further wearable
device is attached to the mobile communications network by means of
communication of the user equipment device with the mobile
communications network.
7. The method according to claim 1, wherein the user equipment
device remains attached to the mobile communications network in the
event of a failure to attach the wearable device.
8. A mobile communications network entity adapted to: perform an
attachment of a user equipment device to a mobile communications
network; and perform an attachment of a wearable device connected
to the user equipment device to the mobile communications network,
the attachment of the user equipment device and the attachment of
the wearable device to the mobile communications network being
performed in response to a single attachment request received by
the mobile communications network entity from the user equipment
device, wherein the single attachment request comprises an identity
of the user equipment device and an identity of the wearable
device, and wherein the mobile communications network entity
authenticates the user equipment device and the wearable device
using a dedicated challenge response mechanism against (i) a
subscriber identity module of the user equipment device using the
identity of the user equipment device, and (ii) a subscriber
identity module of the wearable device using the identity of the
wearable device.
9. The mobile communications network entity according to claim 8,
wherein the mobile communications network entity is adapted to
store the identity of the wearable device, the identity of the
wearable device being linked to the identity of the user equipment
device.
10. The mobile communications network entity according to claim 8,
wherein the mobile communications network entity is adapted to
perform a detachment operation to detach the wearable device from
the mobile communications network while maintaining the attachment
of the user equipment device to the mobile communications
network.
11. A user equipment device adapted to: form a connection to a
wearable device; and attach the wearable device to a mobile
communications network by means of a single attachment request from
the user equipment device for attaching both the user equipment
device and the wearable device to the mobile communications
network, wherein the single attachment request comprises an
identity of the user equipment device and an identity of the
wearable device, and wherein the wearable device and the user
equipment device are authenticated within a mobile management
entity of the mobile communications network with a dedicated
challenge response mechanism against (i) a subscriber identity
module of the user equipment device using the identity of the user
equipment device, and (ii) a subscriber identity module of the
wearable device using the identity of the wearable device.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This is the United States national phase of International Patent
Application No. PCT/EP2017/068884, filed Jul. 26, 2017, which
claims the priority benefit of European Application No. 16181302.7,
filed on Jul. 26, 2016. The entire contents of each of the
foregoing are incorporated herein by reference.
FIELD OF THE DISCLOSURE
The present invention relates to wearable communication devices and
in particular a communication protocol for their operation within a
mobile communications network.
BACKGROUND
The popularity of wearable communication devices like smart watches
or fitness-trackers has increased dramatically during the last
years and expectations of future demand are even higher. In most
cases wearable devices are frequently using wireless data
communication e.g. with the internet, in order to present
information like weather forecasts, information about the
surrounding or personal communication like email or instant
messaging to the wearer. Most services are combined with social
networks and the very essence of these services is connecting users
with each other. On the other hand, the wearable devices become
smaller as size is a crucial factor for the user experience of
wearable devices. Most users of wearable devices also carry a
powerful communication device such as a smartphone almost at any
time of the day. Therefore, a typical wearable communication device
scenario is that a wearable communication device is connected via
short range communication radio technology such as Bluetooth to a
smartphone that acts as a gateway for the wearable device to the
internet Benefits of this scenario are, that there is no need to
implement complex cellular radio technology such as LTE into a
small wearable device. Especially the use of low power Bluetooth is
extending the battery life time of wearable devices far beyond a
scenario in which the wearable device has to implement a complex
and power consuming cellular radio technology.
US 2015/334554 A1 describes a method of using subscriber
identification information stored in mobile user equipment (UE) to
connect to a communication service over a public wireless network
in the UE, establishing a communication link between the UE and a
device, generating network access information (NAI) associated with
the communication service in the UE, and sending the NAI from the
UE to the device via the communication link. The method comprises
connecting the communication service in the device using the NAI
and terminating the connection of the communication service in the
UE.
US 2015/229639 A1 describes methods that allow credentials of a
first client station to authenticate a second client station. The
method includes associating a first client station with a second
client station, the first client station including credential
information, the associating authorizing the second client station
to use the credential information, transmitting, by the second
client station, an association request to a network, the network
utilizing the credential information to authorize a connection, the
second client station configured to perform a proxy functionality
for requests received from the network to be forwarded to the first
client station and responses received from the first client station
to be forwarded to the network, determining, by the network,
whether the credential information received from the second client
station is authenticated and establishing a connection between the
second client station and the network using the credential
information of the first client station.
US 2012/0238208 A1 describes a mobile radio communication device
including a short range radio transceiver. The device may form an
opportunistic network, where a relaying device may be connected to
a cellular radio communication system. The relaying device may
provide access to the cellular radio communication system for
another device using short range wireless communication technology.
The other mobile radio communication device may be informed of
incoming data from the cellular radio communication system via
short range communication from the relaying radio communication
device.
US 2016/0021635 A1 describes a mechanism for connecting a device
such as a parking meter via a UE with a communication link with the
UE being established using, for example, an NFC link, Bluetooth or
WLAN. The device to be connected may or may not include its own SIM
circuit.
US 2014/0169285 A1 describes an aggregating device connected to a
base station with the aggregating device forming a connection to
one or more other devices whereby the connected device is provided
with a global identity.
WO 2012/035335 A1 describes a further example of the connection of
devices to a network using a UE as an intermediary with the network
HLR maintaining multiple records or linking a single IMEI to
multiple devices.
Within existing mobile communication systems, a concept referred to
as a "non-access stratum" (NAS) is employed. The NAS forms the
highest stratum of the control plane protocol stack of the radio
interface between UE and a network entity, e.g. the MME for
LTE.
Main functions of the protocols that are part of the NAS are the
support of mobility of the terminal GUTI (Global Unique Temporary
ID) reallocation, authentication, security mode control,
identification and mobility management information exchange; the
support of session management procedures to establish and maintain
IP connectivity between the terminal and a packet data network
(PDN, e.g. the internet) via a gateway (PDN-GW) at the edge of the
operator network, providing connection management and session
management. In connection management, a service request may be
initiated by the UE to start the establishment of NAS signaling
connection. A paging message may be initiated by the network in
case of downlink NAS signaling to indicate to the UE to start a
service request. NAS messages may be transported, for example SMS
messages together with the generic transport of NAS messages for
various other applications such as location based services.
In session management, there are bearer procedures, which are
network-initiated and provide mechanisms for activation,
deactivation or modification of bearers and transaction-related
procedures, which are terminal-initiated and provide mechanisms for
requests for PDN connection establishment and disconnection,
requests for bearer resources allocation and modification and
release requests.
NAS security is an additional function of the NAS providing
services to the NAS protocols, e.g. integrity protection and
ciphering of NAS signaling messages. From a protocol stack
perspective, the NAS is the highest stratum of the control plane,
at the UE sitting above the RRC layer and at the MME above the
S1-AP layer in an enhanced packet system control plane for E-UTRAN
access.
During the network attach procedure, the network can activate a
default bearer context (i.e. if the terminal requests IP
connectivity in the attach request). Additionally, the network can
activate one or several dedicated bearer contexts in parallel for
several IP connections or different quality of service (QoS)
settings.
The security parameters for authentication, integrity protection
and ciphering are tied together in a security context and
identified by a key set identifier (eKSI). Before security can be
activated, the MME and the terminal (User Equipment/UE) need to
establish a security context. Usually, the security context is
created as the result of an authentication procedure between MME
and UE.
The use of ciphering in a network is an operator option subject to
MME configuration.
From a network operator's perspective wearable communication
devices such as smart watches, which use a smartphone as gateway
into a cellular network, are practically invisible. Only the
smartphone including the user's subscription (SIM/Subscriber
Identification Module) is visible to the operator. Therefore,
cellular network operators are lacking the opportunity to offer
business relationships dedicated to customers with wearable
devices. Also, it is not possible for an operator to optimize the
cellular network for devices "hidden" behind a smartphone.
GENERAL DESCRIPTION
For the development of wearable devices, the size of the device and
the lifetime of the battery are two important criteria. Including a
smart card (UICC) and a cellular radio into a wearable device will
not meet user's expectation of the battery lifetime. Currently most
wearable devices are connected via Bluetooth (low energy profile or
Bluetooth SMART or Bluetooth 4.x all with a reduced radio range up
to 10 meters) with other devices like smartphones. While these
Bluetooth protocols consume several times less energy than cellular
radio communication, most batteries of wearable devices have to be
recharged every second day. With higher power consumption the
device vendor has to implement larger batteries in order to deliver
the same battery lifetime. Also a removable UICC with its
mechanical socket would increase the size of the wearable device.
Both are in contradiction to user's demand for very tiny wearable
devices. Recently, mobile devices incorporating an embedded SIM, or
eSIM, have become available, avoiding the need for a physical chip
card.
The present invention provides a method for enabling a wearable
device connected to a user equipment device to be identified and
authenticated within a mobile communications network, the method
comprising attaching both the user equipment device and the
wearable device to the mobile communications network by means of a
single registration request communicated by the user equipment
device to the mobile communications network. Corresponding network
entities and user equipment devices are also provided.
A wearable device in the sense of the present invention is not
restricted to any device that can be worn in a specific manner
only. Currently, smart watches, smart glasses and smart jewelry
like rings and necklaces are often named wearable devices. However,
the present invention includes a broader definition of wearable
devices including devices within or attached to the human or
animal's body, or on the skin. It includes all devices that are
part of clothing, headdress, footwear, gloves or bags, umbrellas
and other items carried around. Wearable devices can have a user
interface with a purpose to inform a user extensively, like smart
watches, and/or allow human-to-device interaction. A wearable can
also have the sole purpose to sense one or more environmental
parameter(s), e.g. sensors for vital functions like heartbeat,
blood pressure or environmental sensors like audio, video, light,
temperature, or humidity sensors. The term wearable device in this
invention is thus a synonym for any device that has any of the
mentioned restrictions in size, power, or other that let the device
benefit from communicating with a mobile network in the way
described herein.
It is an object of the present invention to allow wearable devices
to be identified and authenticated by the operator network without
the need to implement the device to a full cellular mobile.
This is achieved by enhancing the communication and configuration
between a UE and the cellular core network so that multiple devices
connected with the UE, e.g. wearable devices, can be identified and
authenticate by the core network.
The enhancements are kept to a minimum, i.e. not implementing
cellular protocol stack entities in the connected devices or
additional entities in the UE.
According to known arrangements, the actual identification of a
subscription a device is bound to is done by the USIM. This
principle may be applied in the present invention. However, the
USIM may be present either in the wearable device itself (unlikely
as a SIM card/UICC; more likely embedded) or in the UE as multiple
SIM cards, multiple USIMs (USIM Applications) on one SIM card, the
wearable device subscription is derived from the user's
subscription or one USIM has multiple profiles.
In one aspect, the invention provides a solution to the general
problem of identifying a wearable device that does not have a
cellular air interface implemented from a cellular network.
The invention provides attachment related functions to allow
serving multiple devices even though the main architecture may be
unchanged over existing systems, i.e. each function and each
protocol stack layer exists once in the UE and once in the core
network.
For authentication it is assumed that each device is bundled with
one subscription and each subscription is identified by a single
USIM on the UE side and a single data base entry in the Home
Subscriber Station (HSS) on the network side.
The authentication procedure is performed during a UE attaching to
the network. The authentication procedure may be repeated on
network request while the UE is attached; e.g. as error case
handling. An attached UE is thus authenticated and has a core
network entity associated, in LTE the entity is called the MME
(Mobility Management Entity). The MME has a context for the UE with
certain information relevant for security, service setup etc. An
attach function may fail due to improper authentication which
results in a UE not being served by the network (with exception of
emergency calls).
In order to authenticate multiple connected devices, the UE has to
perform multiple attach procedures which each may fall. In contrast
to attaching the UE itself, the failure of attaching connecting
devices will not lead to the UE detaching or not being served. Also
other connected devices may be successfully attached while a single
connected device is not served.
Therefore, this invention in one aspect provides an adapted attach
procedure, a "secondary attach", that serves connected devices. The
failure of the secondary attach procedure or a later detach of a
connected device (secondary detach) will not result in the network
to release the UE connection unless it goes in parallel to the UE
detach.
Due to the nature of the secondary attach procedure, it may be
beneficial to also install implicit trigger mechanisms on the
network as well as on the UE side so that status updates for the UE
will result in an update for respective secondary attached devices
without the need for further communication over the air. A handover
or cell re-selection by the UE that leads to a change of the
serving core network entity (MME) will result in an update of the
respective information in the HSS for the attached UE as well as
for all secondary attached devices. Detachment of the UE will
result also in detachment of all secondary attached devices.
Through the present invention, the wearable device becomes
addressable, chargeable (billable) and servable by the cellular
network. The operator is able to identify the wearable device in
the network, optimize the network (e.g. with network slicing) for
wearable devices and offer users of wearable devices dedicated
business models. No cellular radio access technology is required to
be implemented in the wearable device, providing extended battery
lifetime and a compact design of wearable device.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of
example only, with reference to the accompanying drawings in
which
FIG. 1 is a message sequence chart for attaching a user equipment
to a mobile network;
FIG. 2 is a message sequence chart for attaching a wearable device
to the mobile network of FIG. 1;
FIG. 3 is a message sequence chart for a situation where a first
attachment attempt of the wearable device fails;
FIG. 4 illustrates an interaction between an MME and an HSS;
and
FIG. 5 illustrates an interaction between an MME and an HSS in the
event of a handover.
DETAILED DESCRIPTION
Referring to FIG. 1, there is shown a message sequence chart of a
known attach procedure according to 3GPP TS 23.401.
As shown, the procedure has the following elements.
A UE sends an Attach Request message as part of a RRC Connection
Setup Confirm message that confirms the setup of a connection
between UE and eNB. An information element Attach Type is set to
"EPS Attach" for normal service or "EPS Emergency Attach" for
emergency services. The UE changes its state from EMM-DEREGISTERED
in EMM-REGISTERED-INITIATED. The UE uses one of its available
identities in the message. For PLMNs where the UE has not
registered before, this may be the IMSI, otherwise it is one of the
temporary identities; e.g. GUTI (Globally Unique Temporary ID). The
UE may send its capabilities and request parameters. These may be
related to DRX, SRVCC, or Proximity Services (ProSe). The UE may
request setup of a default EPS bearer with a session management
message within the same container transported in the RRC message.
Further bearers may also be requested.
After selection of an appropriate MME by the eNB, the Attach
Request message is forwarded to the MME.
If the identity of the UE is not properly known in the MME, e.g.
the UE uses a temporary identifier (in LTE the MME-TMSI as part of
the GUTI) which is not known to the MME, the MME may use an
Identity Request to receive the IMSI of the UE in an Identity
Response.
An authentication procedure is performed between UE, MME and the
subscriber database (HSS) that authenticates the UE utilizing the
UE's USIM and which establishes security means (ciphering and
integrity protection keys).
The subscriber entry in the HSS is updated to reflect the
reachability of the UE via the selected MME.
If a default bearer was requested by the UE, the S-GW and P-GW are
prepared in order to provide the bearer. Further bearers may be
established as part of the procedure or at a later stage.
The eNB is setup to serve the UE with security enabled and
providing the respective bearer service in an Initial Context Setup
Request message that contains the Attach Accept answer of the MME.
The message contains a Tracking Area Identification List with the
tracking areas the UE is now registered in. The message may contain
a new temporary identifier of the UE, especially when the UE used
the IMSI in the Attach Request. The new identifier is stored for
later usage.
The context and bearers are setup and finally an Attach Complete
message confirms the terminated Attach Procedure. The UE changes to
EMM-REGISTERED state.
The attach procedure may also fail due to various reasons. In that
case, the MME transmits an Attach Reject Message (not shown) to the
UE with a reason code in order to provide the cause of the
rejection. The rejection causes currently defined include the
following: illegal UE or illegal ME, EPS services not allowed or
EPS services and non-EPS services not allowed, PLMN not allowed or
Requested service option not authorized in this PLMN, tracking area
not allowed, roaming not allowed in this tracking area and
congestion.
Depending on the cause value provided, the UE will take actions to
prevent or delay future attachments in the same network. Some of
the potential actions are: the UE deletes the stored temporary
identities it was allocated by the network, the UE deletes all
tracking areas (TA) and TA lists stored from the network, the UE
may consider the USIM to be invalid until the UE is switched off or
the UICC containing the USIM is removed or the UE changes its state
to EMM-DEREGISTERED.
Referring now to FIG. 2, there is shown a message sequence chart of
a secondary attach procedure according to the invention which bears
a degree of similarity to the chart of FIG. 1. The message sequence
of FIG. 2 starts from a registered UE that already has a context in
the MME. The UE may be in connected mode, so that it can
immediately send data to the base station, or it may be idle and
needs to establish an RRC connection to send data. If the UE is not
RRC connected and needs to secondary register a connected device,
it will use the RRC Connection setup procedure.
An MME serving the UE is defined, a context exists and security is
established between MME and UE. For the secondary attach procedure,
the following steps apply:
The UE sends a Secondary Attach Request, either in an RRC UL
Information Transfer message or as part of an RRC Connection setup.
The information element Attach Type may be enhanced to indicated
"EPS Secondary Attach" for normal service. This may be especially
useful when the inventive secondary attach procedure is performed
using the legacy Attach Request/Accept/Complete Messages without
defining a set of new messages for secondary attach. The UE
EMM-State of the UE will not change, but the UE has to store the
fact, that an Attach Request has been sent for the new device and
an answer to that request is pending which is identical to having a
EMM-state for the connected device. The UE uses one of the
connected device's identities in the message. For PLMNs where the
device had not been registered before, this may be the IMSI,
otherwise it is a temporary identity which may have been stored in
the UE or the device itself (or it may be stored on the respective
device's USIM). In addition, the UE may provide its own identity
(MME-TMSI) to the MME to indicate which UE is communicating the
Attach Request on behalf of the connected device. This information
may also be implicitly known by the MME due to the communication
connection the NAS messages take, i.e. the eNB may signal the
communication coming from the specific UE. The UE may send in the
Secondary Attach Request the connected devices capabilities as far
as they do not relate to a function that is carried out by the UE,
i.e. DRX and other transport mechanisms are out of scope of the
connected device. The UE may request setup of a default EPS bearer
for the connected device with a session management message within
the same container transported in the RRC message. Further bearers
may also be requested.
The message is forwarded to the same MME that serves the UE.
The MME checks whether the identity provided in the message is
allocated to a connected device and requests the IMSI of the
connected device from the UE if it is not.
The UE, MME and HSS authenticate the connected device using the
USIM of the connected device on the UE side. Security, however, may
not be changed as the UE already has a secure connection to the
MME.
After successful authentication, the HSS entry of the subscriber is
updated to reflect the reachability of the connected device via the
MME. Alternatively, the HSS may be updated to reflect reachability
to be identical with that of the UE. With this, the HSS will update
the connected device's entry autonomously once the UE's entry is
updated regarding its reachability and/or location. Details of this
aspect are described further down this document.
A default bearer may be setup involving the S-GW and the P-GW.
Alternatively, the default bearer of the UE may be used also as
default bearer for connected devices.
Additional bearers may be setup during attach or at a later
stage.
The eNB is updated with new bearer information and identities and
forwards the Secondary Attach Accept message to the UE.
The attach procedure is terminated with a confirmation from the UE
in a Secondary Attach Complete message to the MME.
In case of failure or the secondary attach procedure the
consequences will differ from 30 those of the normal attach
procedure: the UE will stay attached even after a further
attachment of connected devices was rejected and new failure causes
may indicate to the UE that secondary devices may not be supported
by the network (at that time) so that further attachment procedures
are postponed or abandoned.
The above procedures separate the attachment of UE and its
connected devices. However, there may be cases in which the remote
devices are connected to the UE before the UE attaches to the
network. In that case it may be beneficial to perform a combined
"primary" and secondary attach. The message flow is similar to the
legacy attach procedure:
The UE includes a list of devices to be attached into the attach
request.
The MME may fetch additional identity information for each device
from the UE as appropriate and authenticate multiple devices, each
with a dedicated challenge response mechanism (e.g. in LTE it is
AKA) against the respective USIM. As a result of the subsequent key
agreement individual session keys are derived for all devices.
The HSS entries of all related devices are updated and may, as
described above, either be updated individually with the
appropriate location information or the connected devices may
reference the UE's entry so that implicit location updates will
occur when the UE moves in future.
A failure of the attach procedure of one or more connected devices
may lead to the respective device not being reachable by the
cellular network while the attachment of the UE may still be
successfully completed.
New procedures may also be used by the network to handle situations
where connected devices cannot be served or attached. One such new
procedure is shown in FIG. 3. In case of an attachment attempt of a
new connected device by a UE, the network may detect that the MME
currently serving the UE is not able to additionally serve
connected devices.
The network may initiate a change of the MME to have the UE being
served by an MME with remote device supporting ability. The change
may be performed initiating an explicit detach procedure by the MME
with re-attach required which will trigger the UE after 30
successful detaching to attach again.
To finish the secondary attach procedure properly the MME will
reject the request with a reason code that indicates the intention
of the network to allow another attach procedure after a new MME
was selected or in order to select a new MME.
The later attach may then have to be a combined attach, i.e. an
attach procedure for the UE and the connected devices, in order for
the network to be able to property select an MME right away. The
"explicit detach with reattach required" procedure is known from
3GPP TS 23.401 .sctn. 5.3.8.3 in relation to the "selected IP
traffic offload", SIPTO, feature that is not related to the current
invention.
A similar function may also be initiated by the UE, so it detaches
with the aim to attach again. This could be allowed or enforced by
the network through information sent in the Secondary Attach Reject
message. The UE will reattach to the network and the network may at
that point decide to direct the attach procedure to a different MME
that is able to serve the UE and the connected devices. In order
for the network to select an appropriate MME, the UE may be forced
to request attachment of all devices in a combined message. If the
eNB selects an inappropriate MME, e.g. the same as for the last
connection, there are means to redirect the selection to another
MME as shown in FIG. 3 as an example. The procedure above mainly
performs an MME initiated relocation of the serving MME via
detach/attach. Alternatively, a handover procedure could move the
context between MMEs. The more complex detach/reattach process is
used because this relocation function is not foreseen in the
current LTE core network. However, in future systems this function
may well exist:
The MME after receiving a Secondary Attach message and detecting
the MME cannot serve the request may select another MME and forward
the UE context it will also inform the eNB about the change of the
MME and the new MME will send the Secondary Attach Accept message
to the UE.
FIG. 4 depicts a subscriber data base (in LTE this data base is
called Home Subscriber Server/HSS) that is connected example wise
to an MME. A full description of the architecture would show a
single HSS with a number of MMEs in an operator's network but FIG.
4 is a schematic illustration only of what is described in the
following.
It is known for every subscriber is defined by a data base entry in
the HSS of his home operator and a related USIM with respective
identification and security information. Any successful attach
procedure will result in an update in the HSS that updates the
location information, i.e. whether and where (tracking area) a UE
can be reached.
The present invention allows remote devices connected to the main
device (UE) to be attached to the network which leads to a similar
location update in the HSS. This principle is described above in
detail. The MME informs the HSS about changes of the MME to ensure
reachability. This will generate a lot of redundant signalling in
the core network as it is clear from the nature of the personal
area network that the UE and its connected device span that any
update regarding the UE will lead to the same update for all
connected devices.
Thus a further aspect of this invention is the linking of
subscriber based entries. FIG. 4 shows an MME and an HSS containing
three subscriber data base entries with for example the respective
IMSI, an IPv6 address (any many more addresses and parameters)
stored.
A first successful attach of a connected device (secondary attach)
will result in two subscriber data base entry updates: The UE entry
is updated to generate a new forward link from the UE entry to the
first connected device. The respective entry of the connected
device is updated to backward link the entry with that of the
UE.
A second successful secondary attach will lead to another update of
the UE entry adding another forward link and a backward link set
accordingly in the connected device's data base entry.
Curved arrows 10 in FIG. 4 show the links between entry represented
in the data base as location forward links and location backward
links.
FIG. 5 shows the same setup in the case that due to a handover from
one MME to another, for example, the location of the UE is updated
in the MME. The forward link entries in the data base will lead to
an automatic update of the MME address of the connected device with
IMSI #2 and #3 so that these devices are reachable for connection
setup or other services.
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